1. Field of the Invention
The present invention relates to a hand-held power tool and in particular to a hand-held power tool with a working tool periodically displaceable along an axis, such as hammer drill, combination hammer, chisel hammer, impact wrench, keyhole saw, and saber saw.
2. Description of the Prior Art
In a hammer drill, e.g., a drive accelerates a drill along a displacement axis. A pulse and/or a torque is applied to the drill, driving the drill in a workpiece. A complementary pulse that acts in an opposite direction, is applied to the user holding the power tool by the handle.
With periodically or cyclically operated hammer drills, the user must apply correspondingly a counter-force that periodically varies with time. This counter-force is perceived by the user as troublesome vibrations.
To improve the handling of the hammer drill, means is employed that uniformly distribute the generated forces over a period of time. Corresponding damping systems are excited by the cyclically generated forces and dissipate the excitation over a period of time. Alternatively or in addition, the damping systems dissipate the excitation, converting it to heat.
According to French publication FR 22 37 734, a passive vibration compensator is used for preventing vibrations in hand-held power tools.
German Publication DE 815 179 discloses an arrangement of two, axially oscillating, passive vibration compensators along a percussion mechanism for preventing vibrations.
German Publication DE 12 181 970 discloses a passive vibration compensator in form of a hollow cylinder.
European Publication EP 1 710 052 discloses a passive vibration compensator that surrounds a guide tube of the percussion mechanism and is displaced therealong.
Despite the use of numerous and different damping systems, vibrations, e.g., periodic torques, are still applied to a user of a hand-held power tool.
Accordingly, an object of the present invention is a hand-held power tool in which application of torques and vibrations to the power tool user is reduced to a most possible extent.